Electronic devices may be power managed such that components of the device enter a low power ‘sleep’ state when the component is idle. Allowing devices to enter a low power state may result in an overall reduction of power consumption for the device, which can be of particular importance for battery-operated devices or other devices designed for low power operation. To enter the low power state, one or more clock signals to the component may be slowed or stopped. Additionally one or more internal regions of the component may be powered down by having supply voltage reduced or terminated. Some components may be powered off completely when not in use.
When a component in a low power sleep state is to be used, the component may be woken from the sleep state and enter an operational state to perform a set of requested operations. In general, the degree to which a component is powered down determines the length of time required for the component to return to a fully operational state, as the successively deeper sleep states require the restoration of power and state information to a successively larger number of internal regions of the component.